Scottish Labour leader Johann Lamont is facing opposition to her devolution plans from English MPs within her own party.

A number of Labour MPs are understood to have protested against proposals to give Holyrood control over air passenger duty (APD).

They warn giving Scotland powers to cut the levy may pose a threat to airports in the North of England.

Ms Lamont already faces opposition to her proposals to devolve income tax to Scotland from a number of Scottish Labour MPs.

A Devolution Commission set up to look into extra powers is due to report back ahead of the party's conference in Perth next month.

But a number of her own MPs are threatening to boycott the event in protest.

They warn that devolving income tax would mean a cut in the money Scotland receives from the Treasury through a calculation known as the 'Barnett formula', as well as a cut in the number of Scottish MPs.

There is limited devolution of APD to Northern Ireland. But critics of the proposal to give Holyrood similar powers say it would harm airports just over the Border.

A number of English Labour MPs are understood to have expressed their concerns on the issue to the party's shadow chancellor Ed Balls. One opponent told The Herald: "It's an idea that just won't work."

Advocates of the idea argue that it could help increase the number of tourists coming to Scotland.

Others argue that control over the duty could allow new long-haul routes to open up from Scottish airports.

Last night a Scottish Labour spokesman said: "Our test has always been what is in the interests of the people of Scotland and we look forward to setting out our plans to strengthen the Scottish Parliament next month."